Depressive Symptoms: The Interaction between Rumination and Self-Reported Insomnia.

Objective. Prior research has found consistent support that rumination and insomnia are important risk factors for depressive symptoms. The aim of the present cross-sectional study is to examine the interaction between these two previously well-established risk factors (i.e., rumination and insomnia) in the explanation of depressive symptoms. Design. A total of 417 participants (277 women) with a mean age of 39 (SD = 17.59; range 18-85) completed a cross-sectional survey. Main Outcome Measures. Participants filled out the Response Rumination Scale, the Athens Insomnia Scale, and the short version of the Center for Epidemiologic Studies Depression Scale. Results. It was predicted and found that self-reported insomnia moderated the relationship between rumination and depressive symptoms. We found that particularly participants who reported higher levels of rumination as well as insomnia had the highest depressive symptoms. Conclusion. This study is the first to suggest that particularly individuals exhibiting both self-reported insomnia and higher levels of rumination also report higher levels of depressive symptoms. Health professionals screening for mental problems should be aware of this specific combination of insomnia and rumination. Explanations for this moderation effect were discussed in light of study's limitations.